This invention relates to an automotive wheel bearing assembly with a brake rotor.
Among automotive wheel bearing assemblies, there are ones for driving wheels and ones for non-driving wheels. As an example, a wheel bearing assembly for a driving wheel is shown in FIG. 12. It comprises an outer member 3 having two raceways 3a, 3b on its inner circumferential surface, an inner member 1 having raceways 1a, 1b opposite the raceways 3a, 3b, and rolling elements 8 disposed between the outer member 3 and the inner member 1 in two rows. The inner member 1 has a wheel-mounting flange 2. Also, in this example, the inner member 1 has a hole 9 for receiving a drive shaft in its inner circumferential surface. Of two raceways 1a, 1b on the inner member 1, the outer raceway 1a is formed directly on the outer circumferential surface of the inner member 1, while the inner raceway 1b is formed on a separate inner ring.
When wheel bearing assemblies are delivered to an assembling factory of a car manufacturer from a wheel bearing manufacturer, a brake rotor 20, which has been delivered as a separate part, is fixed by bolts 18 to the side 2a of the wheel-mounting flange 2 at the car assembling factory. But if after assembling there is a runout on the side 21 of the brake rotor 20, with the increasing speed of cars, brake judder may occur during braking from high speeds, or brakes may be worn unevenly. With a certain state of runout, brake vibrations may occur even at low speeds.
Heretofore, in order to prevent such runout of the side 21 of the brake rotor 20, when the brake rotor (which has been delivered as a separate part) is mounted to the wheel mounting flange 2 of a wheel bearing assembly delivered from a wheel bearing manufacturer at a car assembling factory, adjustment of phase between the runout of the wheel mounting flange 2 and the runout of the side 21 of the brake rotor 20 was necessary. Such a method is rather troublesome and poor in workability.
Also, at a car assembling factory, due to aesthetic reasons, rust-preventive coating is usually applied to the surface of the brake rotor. If a coating is applied to the brake rotor, runout tends to grow due to uneven thickness of the coating.
An object of this invention is to prevent vibrations and uneven wear of a brake resulting from runout of the brake rotor caused by an increase in the car speed, and to provide a reliable wheel bearing assembly with a brake rotor which needs no troublesome runout adjustment at a car assembling factory.